Cosmic diamonds

Diamonds a billionth of a metre across have been found in space. And there are lots of them. So how are they produced? Nigel Marks was looking at lab simulations which showed production of these microscopic diamonds. It was found that in space, diamonds are formed under conditions that differ from those that produce them on Earth. Now the challenge is to reproduce the supposed space formation method on Earth. Diamonds have a range of applications due to their biocompatibility. This work has the potential to unleash whole new fields for the use of diamonds in health research and in coatings chemistry.

Transcript

Sounds of elephants...

Robyn Williams: That's a lady elephant telling a male to bugger off. He's being a nuisance, both to her and a village full of people.

Also in this unpredictable Science Show is Nigel in the sky with diamonds. He's found trillions of them up there. Nigel comes from Perth, doing research at Curtin University, and their discovery of diamonds in the sky has excited material scientists around the world, because it could be applied here on Earth, in Perth.

Nigel Marks: They're extremely small. They are several nanometres across, which is a billionth of a metre. And even though they're extremely tiny, in space they form in huge quantities.

Robyn Williams: How did you know this?

Nigel Marks: About 25 years ago people were looking at meteorites and they dissolved up these meteorites in acids and all sorts of other gruesome things, and when everything was done, all that was left was this tiny residue of diamonds. And so this has been known for a long time, but what isn't known is how on earth they came to be there and why it is that the universe produces diamonds so easily.

Robyn Williams: And this is where you came into the story. How?

Nigel Marks: We were looking at a completely different problem in a part of science which is called materials science, and we were doing computer simulations to understand an obscure form of carbon coating, and when we were looking at the simulations we noticed something very odd, that sometimes a certain fraction of our calculations produced diamond. And that then set us hunting for where that might happen elsewhere in science and that's where we came across this story in space. I'm not an astrophysicist at all, but in trying to solve one problem in the lab we found something that is related to carbon in the universe.

Robyn Williams: So did you phone an astrophysicist?

Nigel Marks: I didn't, but I emailed a lot of them, and they were very kind, they gave me a lot of their time. And the more we learnt the more we realised that we were on the right track and that we'd stumbled across something remarkably new. And when we published it recently in Physical Review Letters, which is the top place for physics, we got interest from all over the world.

Robyn Williams: What was your explanation as to why it was that diamonds form in space like that in cartloads?

Nigel Marks: Well, this is the strange thing. So the diamonds aren't forming by the way that we're used to forming them on Earth. So we know how they form within the Earth and also in the laboratory.

Robyn Williams: It's pressure, isn't it?

Nigel Marks: That's right, it's pressure. So these ones don't form in the traditional high temperature, high pressure, and that's the thing that's special. So what happens is that first a completely different form of carbon is formed, concentric balls of carbon, a bit like the fullerenes that some people have heard of, and it's fullerenes wrapped inside fullerenes, and those things form easily in space. What we found is that those concentric fullerenes can themselves transform into diamond when they bang into something with just the right energy.

Robyn Williams: I see. And you did say 'in large numbers'.

Nigel Marks: That's right. So in the meteorites around the 1,000 parts per million level these diamonds are formed. So people who go and dissolve up the meteorites find huge quantities of these diamonds. They boil them up and find out what's inside them. So nature is very, very good at making diamonds. It's quite an amazing result.

Robyn Williams: Any particular part of space?

Nigel Marks: Nature forms them basically everywhere. So they're formed when stars die, so-called red giants, that's the first stage where they're produced. They also seem to be produced when the solar system was spinning up. So it doesn't seem as though it's just one particular part of space that does it. As long as the conditions are right, nature will spew them out.

Robyn Williams: How do you spot them from the Earth out in space?

Nigel Marks: Ah, that's very difficult. As yet it is really impossible to look at them unless they get picked up in a meteorite and then caught here on Earth. But having said that, the basic structure of the single ball, the so-called fullerene, they have a particular signal which NASA have picked up with their Spitzer telescope, and recently they found a solid of these balls all packed together. So if space can form these little balls, they can certainly form the concentric balls. They're like Russian dolls, by the way, like carbon Russian dolls, that's a good way of describing them.

Robyn Williams: Well, 20 years ago or whatever it was when Harry Kroto and his colleagues were looking at how this strange carbon, this dusty carbon, this buckminsterfullerene, as it became called, how that might form, they did all sorts of experiments and it didn't happen. Then Harry thought of something amazingly quickly, funnily enough, and he was embarrassed by this, and bingo, there it was. And he got a Nobel Prize.

Nigel Marks: Carbon is a good part of science to get a Nobel Prize. Last year someone got it for graphene, which they discovered by using sticky tape and ripping off some graphite, which is quite remarkable.

Robyn Williams: Yes, two guys in Manchester, Russians.

Nigel Marks: Very good. The easiest Nobel Prize ever, it cost them 20c. We're made of carbon, carbon is an amazing element, and I've worked in it for 20 years and it continues to surprise.

Robyn Williams: Yes, the ramifications...you found the diamonds, they're very small. What's next?

Nigel Marks: What we'd like to do is to reproduce what we think happens in space in the lab. So I've got a proposal in with our Australian Research Council, and we want to build a machine that will reproduce this process precisely in a controlled way in the laboratory. If we can do that, we can create coatings of nano-diamonds, and they are industrially very useful.

Robyn Williams: If you happened to hear The Science Show a couple of weeks ago, a gentleman in Latrobe University was actually talking about getting diamonds inside him which would be transmitters so that you could actually monitor what's going on with, say, cancer patients. Have you thought of that?

Nigel Marks: I haven't, but I am aware that nano-diamonds (which are coincidentally often produced by exploding TNT, which is a very curious way to make diamond) are very important in biology and as bio-markers and for biological attachments. So I'm not surprised to hear that people are looking at those kinds of things. One of the great things about diamond is that it's a biologically compatible, so your body doesn't get upset by it. So our aim would be to produce a machine that would be able to create coatings of diamond. So in industry it's very important to protect surfaces. In fact most of the technology goes into the top 10 nanometres, the rest of it is just there to hold it all together. We would like to develop a technology that would actually be different to the alternatives for producing these nano-diamond coatings, and it should be different, it's got different properties, it doesn't involve high temperature and high pressure. And so it would actually be something that would have a market advantage over the present ways of doing it.

Robyn Williams: And Minister, you heard it first here.

Nigel Marks: That's right. It's always nice to do fundamental research, often by accident you'll end up with something that, who knows, might have a commercial application down the track. But we've got to get our funding first.

Robyn Williams: Same old story, isn't it. But at least ministers or funding bodies know what diamonds are. Nigel Marks is associate professor at Curtin University in Perth in the Nanochemistry Institute.